


The Last Straw

by asmo_enthusiast



Category: Shall We Date?: Obey Me!
Genre: Cuddles, Cute, F/M, Feels, Fluff, Fluff and Hurt/Comfort, Friendship/Love, Hurt/Comfort, Jealousy, Morning Cuddles, Mutual Pining, Pining, Protectiveness, Romantic Fluff, Slow Burn, Slow Romance, Unresolved Romantic Tension, Unresolved Sexual Tension
Language: English
Status: Completed
Published: 2020-05-17
Updated: 2020-05-27
Packaged: 2021-03-02 17:35:22
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 7
Words: 13,438
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/24230677
Author URL: https://archiveofourown.org/users/asmo_enthusiast/pseuds/asmo_enthusiast
Summary: When Kira (MC) sees lash marks on Mammon's back, she decides it's finally time to confront the other demons about the terrible way they treat him. But, when they seem indifferent to it, she decides to get back at them by showing just how much she can care for Mammon. Things get more complex when the evening makes her realise her feelings for him.
Relationships: Mammon (Shall We Date?: Obey Me!)/Original Female Character(s)
Comments: 17
Kudos: 199





	1. Snapping

**Author's Note:**

> This is my first time publishing anything to AO3 so I have no idea if this is going to work. Anyway, in case my tags are all over the place, this is generally a soft, cute fanfic about Mammon and my MC, who's called Kira.
> 
> If you enjoy it, I'd love to know, so I can maybe write similar fics in the future with some of the other brothers <3

Kira knocked on Mammon’s door. No response. She slowly opened the door and stepped inside. She could hear the shower running in his bathroom, so took a seat on the couch, taking out her textbook and balancing it on her lap. Lucifer had tasked her with helping Mammon study for an upcoming alchemy test because, to quote the oldest brother, “no matter how many times he’s punished, that stupid demon never learns.”

Kira smiled slightly to herself, looking around at Mammon’s crazy bedroom. It was extravagant, but not in the same delicate, and decadent way Asmodeus’s was. Mammon’s room was extravagant in a fun way, and he boasted all the things she and him loved to do together, like playing video games using his projector screen, and playing pool or poker on the green felt table. The weirdest object was the vintage car positioned at the top, that would have no use for a demon that could fly wherever he wanted.

“Hmm~ Hmm~”

Kira giggled, able to hear Mammon’s humming as the shower stopped running. She turned that way, as she heard the door open and her mouth gaped in shock as Mammon emerged wearing just a short towel wrapped around his waist.

“HEY!” he yelped. “What are you doing here?!”

“I’m here to study,” Kira said, continuing to shamelessly look his bare torso up and down. Golden abs glistening with specks of water. She breathed a disappointed sigh when Mammon darted over to his walk in closet, leaving wet footprints as he went.

“You- You can’t just look at me like that!” Mammon complained, before suddenly yelling, “who the hell’s taken my clean clothes?”

Kira smirked, remembering her shift keeping guard for Leviathan earlier that day when he’d decided to threaten Mammon into giving his money back by stealing his clothes. It was a plan that she’d questioned at the time, but now she was faced with an almost naked, furiously blushing Mammon, she didn’t feel all that bad about it anymore.

“Hey! You know something, dontcha?” Mammon said, noticing her expression.

Before Kira could deny her involvement (not that that would’ve been honest), Mammon had darted across the room to her and shook his head like he was a wet dog, splattering her with water. 

“Mammon!” she giggled, “you’re getting it on my book!”

Mammon, loving the smile on her face and greedily wanting to do everything he could to see it, tried to shake a little more, until his white hair was its regular mess again, rather than the mop it had been before.

Kira’s smile suddenly faltered, and Mammon immediately looked down at his crotch, wondering if the towel had fallen, but a gentle finger running along his spine told him that wasn’t the case.

“What’s- What’s wrong?” Mammon asked, stammering because even the smallest platonic touch from her was translated into something erotic in his brain.

Kira’s expression remained deadly serious.

“Sorry about your textbook,” Mammon said, snatching it off her lap and wiping the water droplets off the cover. It also worked as a good escape from her touch.

“Mammon…” Kira began. “Are those lash marks on your back?”

Mammon broke into a carefree smile, turning around and trying to reach the long red scratches he now knew she was talking about. “These? It doesn’t even hurt. Not for The Great Mammon, anyway! You don’t need to wo-”

But, Kira was on her feet. She took one more look at his back, narrowed her eyes and hurried out of the room. Mammon quickly pursued her, snatching his bathrobe as he went and tugging it onto his shoulders.

“Kira, where are ya’ going?” he asked, catching up to her when she was halfway down the stairs.

“I need to have a word with Lucifer,” she said sternly.

Mammon looked at her and raised his eyebrows, feeling a pang of jealousy. “You- You do? I, uh, thought we were gonna study - well, play video games, more like, but...”

Kira turned to Mammon, grabbing him severely by the shoulders. She was a little shorter than him, and a lot weaker, so he didn’t feel threatened, but he flinched back nevertheless.

“Studying can wait,” Kira muttered, and Mammon nodded his agreement without even questioning what had caused her sudden change of heart. Then again, she could tell him she was going to commit treason against Diavolo, and as long as she held his shoulders like this, he’d probably blindly agree.

With Kira’s furious walk, they arrived in the common room in no time. Mammon’s bare feet were warmed the instant they stepped into the place as the heat from the fireplace circulated the room.

“Have some decency Mammon,” Satan said, looking up from his book and deciding that Mammon’s bathrobe secured with just a thin silk string around his waist was not offering enough coverage.

Beelzebub, however, seemed far more irritated by seeing Kira and Mammon together in that state and his stomach wasn’t the only thing that growled as he looked at them.

“Were you two showering together?” Asmodeus, who was painting his nails on the back table, asked suspiciously.

Kira immediately glared at Asmo. “Do I look wet to you, right now?”

Asmodeus giggled, unable to hold back his usual dirty mind. “Well, Mammon certainly does.”

Kira didn’t give him a chance to say anything else though, and turned to the only other brother in the room: Lucifer. The oldest was shuffling through some student council paperwork, but felt her eyes burning into him, and looked up.

“Yes, Kira, what is it?” he said. His tone suggested that she often demanded a lot of him, but he knew that wasn’t the truth at all and that the irritance slipping into his voice was as a result of seeing her and Mammon together, looking like they’d just had sex.

“Look at this,” she huffed, before seizing Mammon and turning him around so that his back was towards his brothers. She yanked the bathrobe down his shoulders, so that it hung around his waist, and she gestured to the multitude of red lash marks.

Mammon blushed at being so swiftly undressed by Kira, and shrugged the material back up his shoulders. Kira, having presented her evidence to the jury, crossed her arms and waited for anyone to speak.

“Yes, it’s some marks on Mammon’s back, probably from him getting in trouble, again,” Lucifer stated.

Kira hissed. “That’s all this is to you? You see his back looking like someone’s torn all the skin off of it and you think it’s just whatever? Don’t you wonder whether he’s in pain?”

Mammon grabbed Kira’s shoulder and tried to persuade her to tone it down. “Calm down. It’s not that bad…”

“You know what. This is the last straw!” Kira continued passionately. “All six of you treat Mammon like trash and I’m done turning a blind eye to it. Yes, maybe Mammon steals sometimes, and he doesn’t pay you back, and sometimes he’s stupid, but that’s like having a go at Beelzebub for eating too much, or Asmodeus for being horny! Mammon’s heart is fifty times the size of yours, Lucifer. So if you dare lay a hand on him again, I don’t care if you’re torturing him, whipping him, or just slapping him on the back, I will never speak to you again!”

An uneasy silence fell across the room. Then Lucifer broke it, with hollow laughter.

“Kira, I think you misunderstood,” Mammon began. 

Part of him wanted to leave the misunderstanding, because he’d never heard someone say such nice things about him and his heart had never felt so warm, but there was also the angel on his shoulder telling him that it wasn’t fair on Kira because she’d just feel stupid later when she heard the truth.

“These marks aren’t from Lucifer,” he admitted. “They’re nothing to do with my brothers, actually…”

“They’re not?” Kira said, turning to him.

Lucifer’s hollow laughter continued and then he said coldly. “I didn’t realise you felt so strongly about my mistreatment of Mammon.”

Kira refused to let the embarrassment seep into her face. She kept a steady scowl and said seriously. “Even if these marks aren’t from you, everything I said still stands. Come on, Mammon.”

She grabbed Mammon by the hand and pulled him out of the common room. Once the sound of their footsteps grew distant enough, Lucifer put his head in his hands.

“I thought it didn’t bother you, hence the evil laugh,” Satan said, smiling now he was seeing Lucifer’s actual irritance at what had just happened.

“I’m now not sure whether it’s Kira with Mammon wrapped around her finger, or Mammon with Kira wrapped around his,” Asmodeus noted. He’d resumed painting his nails, but he too couldn’t concentrate properly after seeing that display, and he managed to miss his nail entirely, getting a splodge of pink on the table.

Lucifer sighed in aggravation. “Do you think I’m in the wrong here?”

Satan was rendered silent, taken aback at Lucifer asking that to them. He wasn’t the type to regularly reach out, especially questioning his own morals like that.

“Is it a trick question?” Beel muttered.

Lucifer looked towards him and shook his head.

“Then yes,” Beel said quietly. “I think Kira’s right. Maybe we’re all a bit too harsh on Mammon.”

Asmodeus laughed coldly. “You think? If he didn’t do stupid things, we wouldn’t criticise him for them.”

But, Satan was on Beel’s side and he added wisely, “yeah, but she isn’t wrong about him being good at heart. He’s never harmed her, or pushed her to do anything with him, which shows a lot more restraint than any of us have.”

“Ridiculous,” Lucifer muttered. “Only she could make us have this discussion.”


	2. Healing

**Summary for the Chapter:**

> Back in her room, Kira decides to take care of Mammon's injuries.

Kira and Mammon were back in her room. She’d dropped into Levi’s room on the way, finding it empty, and grabbed Mammon a change of clothes, but her textbook was back in his room and, after that ordeal, she didn’t have the energy to go and get it.

“I guess we’re not gonna study,” Mammon said awkwardly.

Kira didn’t care about that. She dragged Mammon over to her bed and ordered him to sit. “I have some ointment in the bathroom. One moment.”

In the few minutes Mammon waited, hearing cupboards slam in the bathroom, and also a loud bang that might have been Kira punching a wall in frustration, he tried to gather his thoughts on everything he’d just witnessed. He knew it was wishful thinking, but the way Kira looked out for him back there and unleashed her fury upon Lucifer and the others with no fear made him wonder if something had changed between them. Maybe he was a special person to her? She was back before he could answer his own theory.

“Did ya punch a wall back there?” Mammon asked, trying to get a look at her red knuckles.

“I- I’m just frustrated,” she muttered, taking her place beside Mammon and opening the jar of pain relief ointment.

Mammon sighed with relief as the cool cream was rubbed against the harsh red gashes. He’d been lying earlier when he said they didn’t hurt and he knew that Kira had known that, as she was very gentle with her touch.

“Mammon,” Kira began. “I want you to know that I was being honest back there.”

Mammon shushed her slightly, “I know…”

“And I was serious about these lash marks,” Kira said, running a finger along the length of one.

Mammon wanted to wince, but in the moment, with her hands massaging his back, it came out as a moan. She didn’t seem to take it weirdly, probably assuming he was just in pain, definitely not pleasure.

“How did you get these? If not Lucifer…” Kira asked.

“I had a run in with some demons,” Mammon explained, trying to reassure her as best as he could. “They had real nasty tails, and they sorta knocked me around a bit. ‘Course, I beat em in the end.”

Mammon couldn’t bear to tell her the real reason he’d got in the fight. He could already imagine the way she’d blame herself for his wounds if she found out that he’d overheard two demons saying disgusting things about her and had exacted revenge in the only way he knew how.

“I don’t know how much I believe you,” Kira murmured, but she decided it was best to leave it at that.

Mammon whimpered once she stopped touching his back, longing to feel her hands on him again, but the moment was over.

“I’m going to grab my textbook from your room,” Kira said, getting up.

“We’re still gonna study?” Mammon whined.

Kira shook her head, reaching out to pat his still damp hair. “Probably not, but it’s the perfect excuse to go back to your room and grab an extra controller.”

Mammon broke into a mischievous smile. “I’ll wait here then.”

“Sure, but don’t you dare go snooping through my closet looking for something you can sell,” Kira pointed a finger at him.

Mammon chuckled, knowing that he’d never sell any of her stuff, and thinking of the small collection of her clothes and things that he had gathered in his room - not on purpose, of course. She’d just left them there a while ago and he’d never bothered reminding her to collect them. Anything that carried her scent was a treasure to him, even more than the Grimm he was always so desperate to have.

Kira left Mammon in her room, and headed down the hallway. The concerns circling her mind about his injuries had her completely preoccupied, and she hardly noticed her wrist being seized until she’d been dragged into Leviathan’s room.

“Levi, what’s going on?” Kira asked, and she sounded exhausted.

Levi’s surveyed her with furrowed brows, but nothing looked too out of the ordinary. In fact, her slightly narrowed eyes made her look even cuter and he almost forgot why he’d originally brought her in here…

“Is it true you yelled at Lucifer?”

Kira sighed irritably, recalling that news never seemed to spread this fast in the human world. “Believe whatever you want.”

“No… No! I want to hear the truth. Satan didn’t give me any explanation when he came upstairs and then Asmo described it as a ‘lovers quarrel’ and now I feel left out,” Levi ranted, his orange eyes sparking with envy. He looked concerned. “Tell me what happened.”

Kira sighed again, but she could tell Levi’s heart was in the right place, so she admitted quite vaguely, “we had a one-sided disagreement over how he treats Mammon.”

“Mammon?” Levi repeated, shrugging. “What’s wrong with how he treats Mammon?”

“The way he treats Mammon is-” This time, Kira’s sigh sounded aggravated, and Levi took a step back. “You know what, you’re all the same, and I can’t get through to any of you,” she muttered. “Mammon’s waiting for me.”

After that run in, and well aware that Belphegor, the other brother that hadn’t been present in the common room, would soon wake up from his mid-evening nap and have his own questions for her, Kira rushed in and out of Mammon’s room, grabbing the textbook and a controller as she went, and arriving back at her own room in record-breaking speed.

Mammon was lurking near her vanity when she entered the room, wearing his clean clothes, and she hissed to announce her arrival, making him flinch away from whatever he’d been calculating the worth of. Maybe another time, she would’ve made a comment about his greed, but today that would be entirely going against what she’d just preached to Lucifer. Knowing that, she critiqued him on something different.

“You should’ve stayed put,” she said. “You’re my patient today and I’m putting you on bed rest.”

“But, we’ve gotta go get dinner soon,” Mammon noted, as he found himself steered back to the bed by an invisible force.

“I’ll bring you dinner up here,” Kira said. She joined him on the bed, crossing her legs under her and then holding up the two items she’d brought from his room. “Video games or studying,” she proposed, raising each of the objects accordingly. “Video games or studying,” she repeated.

“Neither,” Mammon said, after a moment of debate.

Kira glared at him, dropping both the controller and the textbook with a thump. “What are we gonna do until dinner then?”

Mammon shrugged, laying back on her bed and immediately wincing when the lash marks were met with another layer of pressure.

“We can watch a movie,” Kira suggested. “Or…”

With his eyes closed, Mammon couldn’t see why she’d drifted off, but a sudden shift of weight on the bed meant his eyes opened wide. Then, he could only gasp. Kira was practically on top of him, straddling him, with a sadistic smirk on her face.

“We could do other things, you know,” she said teasingly, placing a firm palm on one of his pecs.

“K-Kira,” Mammon stammered.

He was glad when she grabbed her pillow and smothered his face in it, covering his blushed cheeks, although the instant his world was plunged into darkness, he found himself missing her evil smile. The weight on his body lifted, and when he peeked over the pillow, he found her perched on the other end of the bed.

“Who- Who the heck are ya? Asmo- Did he teach ya this?” Mammon managed, while propping himself back up against the headboard. He felt less vulnerable to her charms that way, even if it wasn’t the truth.

Kira giggled airily. “I was just joking,” she said.

Mammon muttered something barely coherent. “Well- Ya- You’ve gotta be more careful doin’ that. I’m… Safe, but- The- The others might not realise you’re jokin’.”

“Did I hurt your back?” Kira asked, melting his reserve with innocent, apologetic eyes. “Sorry. I was too rough with you.”

“Ya’- Ya’ can be rough with me,” Mammon said, furiously blushing still. “Just- Just don’t catch me off guard like that…”

Kira tried not to read too much into his words. She knew it was just her frustration translating the things that Mammon was saying as having lewd connotations.

“Let’s play some video games,” Mammon said, snatching the controller and then sliding down onto the floor to switch on the console and to get a safe distance from her.

Levi came by Kira’s room almost as much as he did, and it meant she had a good stack of video games by the TV unit. The three of them would usually play together, sometimes with Beel, Belphie and Asmo going in and out of the room, but Mammon felt smug, knowing that this time Kira was dedicating her all to him.

“Thought you didn’t wanna play video games,” she muttered bitterly, while he put the disk in.

Truthfully, Mammon couldn’t tell her what he really wanted to spend this alone time with her doing, so he’d decided that they should at least do something fun to make that time less agonising. He didn’t mind that he’d gone back on what he’d said earlier, and he stuck his tongue out at Kira before joining her on the bed again.

Playing a racing game against each other, they passed the time without even realising it was going by. If it wasn’t for dinner, Mammon expected Kira would’ve carried on playing forever - or at least until she ranked above him on the leaderboard.

“I just let you win because you’re hurt,” Kira lied, rolling around on the bed in frustration.

“Oh yeah?” Mammon said, unconvinced.

Kira buried her face in the bedsheets. “I normally win…”

“That’s because normally I let ya’,” Mammon murmured, quiet enough that she couldn’t hear it. Her senses were muffled by the smothering of the duvet, and he grabbed her by the collar of her shirt, tugging her back into the light.

“Okay, okay,” Kira grumbled, getting up. She smiled at Mammon, while sliding her arms into a leather jacket. Evenings got pretty cold in the House of Lamentation - and none of the demon brothers seemed to mind having to lend her their jackets or cuddle up close to her by the fire, so they’d never done anything to help make the temperature more human-friendly.


	3. Dining

**Summary for the Chapter:**

> Kira ventures to the kitchen to grab dinner for Mammon and herself, but she's unable to avoid a confrontation.

They normally had dinner in the dining hall, but Kira had decided she’d be best avoiding the other demons by heading straight to the source of the food - the kitchen. Unluckily, she’d timed something wrong along the way: maybe she’d skipped a few too many stairs, and she was confronted as soon as she reached the fridge door.

“Kira?”

Of course. The demon on cooking duty tonight was Belphie. Kira’s heart sank, but she turned around, removing her hand from the fridge door and making wary eye contact.

“Good evening, Belphegor,” she said. Hopefully, keeping things brief and formal would prevent him from mocking her or asking her too many questions about her display earlier.

Belphie, however, wasn’t going to let her get away that easily.

“Aren’t you coming to dinner?” Belphie asked, trying to prompt her into saying something incriminating. When she didn’t take the bait, he continued, “are you scared Lucifer might eat you instead?”

“No,” Kira snapped in outrage, “I’m not scared of him. I’m just ignoring him until he apologises to Mammon. I’m ignoring all of you. Mammon and I are gonna have dinner in my room”

“Me included?” Belphie scoffed, trying to hide his real irritation at hearing himself grouped in with the others so casually. “Why? Because every now and then I tell Mammon to shut up?”

Kira huffed, but turned her back to him. She didn’t want to have another shout-off with one of the guys tonight. She just wanted to bring some good food back to Mammon. Hell-Sauce noodles will do, she thought and slammed the fridge with enough strength that it made her point to Belphie. She stood on her tiptoes and reached into one of the top cupboards, not bothering to check if the youngest had gone. Even if he lingered in the room, she wasn’t going to talk to him anyway.

“Kira…”

So he was still there.

She felt his presence directly behind her, and then his arms snaked around her waist, hugging her from behind. He locked his arms together, trapping her in the back hug, and he inhaled the smell of honey when he buried his face in the nape of her neck.

“Come to dinner,” Belphie said smoothly. “I don’t want you to go back to Mammon.”

She wasn’t about to give Belphie a free pass, just because he made her heart skip a beat. He was just as nasty and degrading as the others when he wanted to be - sometimes more. It really depended on how much sleep he’d got, whether he was going to act like a malicious demon, or a person.

She raised her shoulders, preparing to exert all her force in shrugging off his embrace, but she didn’t have to. Another arm entered the fray, reaching up past her and Belphegor, and grabbing two cups of Hell-Sauce Instant Noodles. The jacket sleeves rode up slightly as he reached over the top of them, and Kira recognised the slightly freckled complexion of Beelzebub’s arms. She waited for Belphie’s grip to lessen, which didn’t take long now his twin was in the kitchen, and then pulled away while she had the chance.

“Thanks Beel,” she said, gathering the food she’d found in her arms.

“I guess you won’t be at dinner,” Beelzebub noted. He seemed to understand what had gone into that decision, and he smiled slightly to show that there were no hard feelings between them.

Kira nodded her head, keeping half an eye on Belphie, who was slinking around the edge of the room to loot the fridge.

“They’re Mammon’s favourite,” Beel said, gesturing slightly to the noodles, “he’ll be happy.”

Even though she’d earlier grouped Beel in with the others as one of Mammon’s bullies, she felt guilty for that now. Beel was a sweetheart, and she could only imagine the turmoil he was in now that she and Mammon had both locked themselves away. He was the type who’d blame himself for not doing anything, even though he hadn’t been the main perpetrator of the abuse.

“I’m sorry,” they both said at the same time.

From behind them, Belphie muttered, “thought I was the one with the twin telepathy.”

“Sorry I clumped you with Lucifer,” Kira finished, once Beel had gestured that it was okay for her to go first. “You’re not the same as him, and it wasn’t fair.”

“No, you’re not entirely wrong,” said Beel. “I’m a pretty terrible little brother to him sometimes… I should apologise to Mammon.”

“Ha!” Belphie scoffed maliciously from the back. “Always so noble, Beel.”

Kira ignored Belphegor’s sarcasm, going so far as to gently touch Beel’s cheek, turning his attention back to her. 

“Maybe tell him tomorrow,” Kira said. “At the moment, I just want to spend some time helping him feel better, and I feel like if I let you in my room, it won’t be long before Asmo and Levi and everyone invite themselves in as well at which point, there goes my plan to make Mammon feel better.”

Beel just about managed to conceal his displeasure at the idea of Kira nursing Mammon back to good health by turning away for a moment. Belphegor was less subtle.

“I bet Mammon’s lapping this up,” he cursed, eyes narrowing at Kira.

But some kind of lesson had been learnt in the kitchen today, as Belphie knew he was getting nowhere and prowled out of the door, leaving Beel to help Kira grab the final few ingredients for her and Mammon’s meal.

“I’m hungry,” Beel murmured, his stomach rumbling affirmative. “Have a good dinner.”

Kira nodded her thanks to Beel, and then made her way back up to her room. This time, Mammon was on the bed when she got in, following the doctor’s orders and scrolling through his Devilgram feed to keep himself busy and so that he didn’t start missing her too much.

“Okay, I’ve got two Hell-Sauce noodles, homemade cookies from Purgatory, some kind of hot sauce Beel recommended - although God knows why you’d need to make those even spicier - and our drinks, sir, of course, the Devildom’s finest Sickly Soda,” Kira finished, presenting the stuff on the tray she’d carried it all upstairs with.

Mammon chuckled at her performance, then started to swing his legs off the bed. Kira had already headed into the other section of her room and was setting up their noodles, pouring water from the kettle in, and then sealing the lids. He wandered over to join her, and she hurried to pull out the chair for him.

“This feels sketchy,” Mammon said, but he took the seat, trusting Kira not to pull it out from under him, as his brothers often did.

“I’m just being nice,” Kira narrowed her eyes at him, but went to take the seat opposite. “It would be a bit rich if I did anything else after shouting at Lucifer.”

“A- About that,” Mammon began, “ya’... ya’ really did a good thing back there. Thanks.” 

He had been staring into his lap while saying that, but was curious to see her reaction, so he warily looked up.

“I like it when you thank me,” Kira smiled to herself, busying her hands with peeling the lid off Mammon’s Hell-Sauce noodles and then stirring in the sachet of seasoning. Because he wasn’t sincere with her often enough, it always caught her off guard when he suddenly got sentimental. “Ow!”

“Hey!” Mammon suddenly pushed her hand away, sacrificing his own hand which was met with a burning jet of hot steam.

“Why’d you do that?” Kira said, grabbing Mammon’s hand and flipping it up and down, checking for burn marks. Luckily, his demon skin was a lot harder wearing than hers, and any redness was quickly swallowed up as he healed.

His human, however, had not been so lucky and Mammon took her hand in his, nursing the scalded mark that had blossomed on the back of her hand. He glanced up at her from beneath furrowed brows and then gently blew on the red burn, cooling the skin. Kira winced, but her pain was dispelled by a whole other feeling. Mammon taking a moment to inhale was her chance and Kira tugged her hand away from him.

“You’re so stupid,” Mammon muttered, but his expression contrasted what he was saying with utmost concern.

“You’re stupid too,” Kira murmured, doing everything in her power to avoid eye contact. “You shouldn’t put yourself in danger to save me.”

“Danger?” Mammon chortled, “it’s hot steam.”

But, after a moment of watching Kira study her burn, his resolve melted.

“But that… That doesn’t mean ya’ should put yourself at risk either! I- I’m a demon, so it’s alright. But, you’re just a human, and you’re a magnet for danger,” Mammon lectured. After Kira smirked back at him, he hurriedly grabbed the nearest noodles to excuse his blush as just a reaction to the spiciness and, having not been stirred properly, scooped a large clump of burning hot noodles into his mouth.

While he gasped for air and stuck his tongue out desperately trying to cool his mouth, Kira sighed, but instinctively opened his can of ice cold soda and pushed it across to him. Mammon gulped it all down in one, chilling his burning tongue while Kira’s mind strayed again as she glued her eyes to his Adam's apple and the few droplets of condensation that rolled down his chin.

“What are ya’ lookin’ at?” Mammon growled, taking a sharp intake of breath as he banged the can down on the table.

Bravely, Kira reached across the table and wiped the stray droplet off his chin. She sensed him freezing up, and removed her hand as quickly as she’d placed it.

“Let’s just eat,” Kira murmured, drying her hand with the hem of her shirt.

Across the table, Mammon squirted extra hot sauce on top, and Kira wondered whether he knew what he was doing to her, especially as him engaging in the completely separate action of blowing on the steaming noodles was only reminding her of the tingling sensation of him blowing on her burn.

“Just eat,” she repeated, when Mammon noticed her tsk loudly at herself and stared at her, bemused. He didn’t stop staring. “Mammon,” she barked, “eat.”

Mammon scrambled to pick up his chopsticks again and continue, but he was clumsy with them. Kira broke the awkward silence by laughing at his fumbling.

“Hey!” Mammon yapped, “you’re a terrible nurse! You should be feedin’ me or something instead of just watchin’ me struggle!”

Kira shot him an incredulous look, before drawing a line with her fingertip. “I’m trying to work out the connection between you hurting your back, and you not being able to hold utensils properly. Hm…”

Mammon glared at her, but at least they’d broken the ice after the tentative gazes that had resulted from their joint injury. They were able to slurp their hell-sauce noodles with ease - or as much ease as Kira could, given that they were spicier than anything she’d ever tried in the human world - while making regular jabs at each other and sliding back into their normal ways.

“So these are Luke’s famous cookies?” Mammon asked, sniffing the cookie dubiously.

“Luke’s and Solomon’s - although he assured me Solomon had minimum input, so I don’t think they’re poisoned.” Kira bravely bit a chunk of hers and after a moment of the sweet biscuit melting in her mouth she smiled warmly. “Mmm. Luke’s clearly getting good. He’ll be competing with Barbatos in no time.”

“An angel competing with a demon?” Mammon aggressively took a bite out of the cookie and chewed it with fervour, “pfft, that’s a battle they’ll never win.”

Kira restrained from making a distasteful joke about the Celestial War, instead opting to tease Mammon, who’d just devoured the exact same cookie he was claiming was ‘disgusting’.

“If all the angels in the Celestial Realm are like Simeon and Luke, maybe I should cancel my second year of the exchange here and head over there instead,” Kira suggested, as if in passing. “Especially if they all look like Simeon…”

“H-Hey! That’s- That’s some very unholy thoughts you’re havin’ there!” 

He’d hardly swallowed the cookie, and it meant he choked out the words. Kira laughed, but handed him the remainder of her can of soda, so that he could ease his sore throat.

Mammon shook the empty can, his cough subsided. “Ah, sorry. I finished it.”

“You just indirectly kissed me,” Kira joked, definitely not expecting the extreme spluttering reaction from Mammon. “God! Mammon, I don’t have any more drinks to give you, so if you could stop choking every few-”

A knock on the door stopped her in her tracks. Kira’s expression instantly sank, and she excused herself, ordering Mammon to stay put.

She opened the door forcefully, eyes narrowing at the person behind the door, before she’d even registered who it was, but when Leviathan looked back at her, with wide apologetic eyes and he gulped nervously, her anger subsided.

“Kira,” Levi said tentatively, “I brought manga, and games…”

Kira looked down at his stack of goods and noticed the thoughtful placement of the new volume of her favourite shoujo series on the top.

“Can we hang out?” he asked innocently.

She noticed him glancing past her into the room, but Mammon - whether under the power of their pact, or maybe just because he was sneaking another of the cookies he ‘hated’ - was tucked off to the side, out of sight.

“Yes, he’s in there,” Kira stated, knowing exactly what he wanted to ask, even if he wouldn’t dare say it.

Levi craned his neck. “He is?” He glared at the wall, behind which Mammon was probably cramming cookies into his mouth. “W- Why are you two still together? I mean, are you doing this because you feel obliged after lecturing Lucifer? He’s not even THAT hurt. I don’t understand what’s so much better about Mammon than me. Yeah, I guess I’m a nasty otaku, but-”

Kira’s eyes narrowed, and Levi realised that, in his bubbling envy, something had slipped out. She didn’t mind his self-deprecation, in fact it made her want to hold him. She didn’t even mind him questioning her motives for looking after Mammon, because she too had wondered whether she was trying to prove to Lucifer that she could treat him well. What had made her so angry, was Levi telling her that Mammon wasn’t even that hurt, when she’d seen him wincing over the lash marks just minutes ago when he’d leant back in his chair. It was exactly what the brothers always assumed: nothing they could say would affect Mammon. Kira had seen firsthand that he was affected.

“Levi, I’m not hanging out with you tonight,” Kira began, purposely acting spiteful, “I’ll be sleeping with Mammon in here. Complain to Lucifer or whatever, but make it quite clear to your brothers that if I see any of them before breakfast tomorrow morning, I will make them wish I could physically kill them.”

Even though she’d intended to hurt him with her words, seeing Levi’s face flush red, mixed in anger, envy and embarrassment, she felt guilty. He dropped the pile he’d been holding onto the hallway floor, just outside of her doorway, and then darted off. Maybe he’d used his magic, because he disappeared quicker than lightning, and she couldn’t even apologise for being too harsh.

“Huh? Who was it?”

Kira pivoted around, placing her hands on her hips. “It was Levi, and it appears I scared him off.”

Mammon, concealing his smile because she was looking quite severe, had to agree. “You are kinda…”

She glared at him, and he felt the chill wash over him, affirming his point.

“Anyway,” Kira moved on. She and Mammon halved the pile of books and games and carried them into the room while she explained the plan. “You’re sleeping with me tonight.”

A loud bang echoed around the room as the top book slid out of Mammon’s hands and onto the floor. He didn’t even make an effort to receive it though - rather, he just stared at Kira’s bed, in a daze.

“Careful,” she lectured, bending down and retrieving the book. She wiped the cover down, checking it hadn’t been damaged. Levi wouldn’t be happy if it was.

“Y-You just said we’re going to- To sleep together,” Mammon repeated, daring her to deny and tell him he’d been imagining it. He wasn’t convinced he’d heard it right.

“Yes. I’m going to protect you tonight,” Kira said firmly.

Mammon in no way wanted to deny her offer, but he couldn’t help grumbling, “you can barely keep your own butt out of trouble, how are you plannin’ to protect me?”

Kira heard him and responded boldly. “I’m going to hold onto you.”

Blushing furiously, Mammon clutched his aching heart. He wished he could return her words right back at her. He still wasn’t sure why he couldn’t…

“Kira, d-don’t just say things like that,” Mammon forced, his hunger to touch her and love her translating into an irritated tone.

She didn’t seem to understand what she’d said to make him sound like that, and she tilted her head curiously. “What’s up? You’ve slept in my bed before…”

“Only by accident!” Mammon protested.

Kira was unfazed. Instead, she made Mammon follow her around the room, to her closet, where she grabbed him a fluffy hand towel. She pressed it into his open hands, and then, knowing he couldn’t protest, reached up a fraction to lovingly rustle his hair.

“I put your toothbrush in the left cupboard,” she said. “Don’t get it confused with Belphie’s - his is on the right. Oh, and use my toothpaste. Levi finished yours the other night, sorry.”

It was a relief that her small hand was still planted on his head, because it worked as a calming influence on her demon, even as she reminded him that he was no more special than his brothers that slept here regularly.

Mammon headed into the bathroom, leaving Kira to change into her pyjamas. He’d promised not to open the door until she called for him and confirmed she was decent.

After splashing his face with cold water, relieving some of the red flush from his cheeks, he opened the right cupboard and realised that his temperament was not going to be so easily cooled. Snatching Belphie’s toothbrush, he chucked it in the bin without hesitation. The even nastier option would’ve been to dip it in the toilet and then put it back on the shelf, but Mammon wasn’t that bad, and Belphie was still his little brother. Disposing of it altogether, only to then replace his own toothbrush in the identical spot would reclaim his territory well enough.

He aggressively brushed his own teeth, taking an extra second once finished to have a snoop around Kira’s bathroom. Asmo’s face cream went straight in the bin, and soon Beel’s deodorant had been given identical treatment.

**Notes for the Chapter:**

> Thanks so much for all the support on the first two parts! I'm really enjoying writing for Obey Me so I'll try and keep updating this consistently! <3


	4. Caring

**Summary for the Chapter:**

> Mammon and Kira tuck into bed, and she tries her own form of magic to heal his wounds.

“Can I come out?” he asked, rapping on the door until his knuckles ached.

“Geez, Mammon, gimme one sec,” Kira called from the other side, and he heard her fumble around and something crash from inside her room. “Okay, I’m changed.”

“Are you sure you were just getting changed,” Mammon muttered, as he opened the door, “it sounded like ya’ just broke something-”

He trailed off, looking at Kira.

“That’s my shirt.”

Kira looked down at herself and then back up at Mammon. “Hm? You must’ve left it here. It’s comfy and it totally suits me better than it suited you. Can I keep it, Mammoney?”

Mammon shrugged, pretending he was invincible to the cute nickname. “Y-yeah. Keep it. You… look cute, I guess.”

“Was that a yes? You started mumbling, so I couldn’t tell. Guess I’ll just keep it anyway,” Kira said confidently, knowing that Mammon wasn’t about to tear the shirt off her body. Now she thought about it, that would be an interesting turn for the night…

“Why are you blushin’?” Mammon asked, wondering why she looked the same way he probably did, when there was no way she could be going through the same problems he was.

Seeing her in his clothes felt like he’d just claimed her as his. He got excited at the thought of his brothers seeing her dressed like that and getting jealous of him. Normally things happened the opposite way round, and he was almost irritated by the fact that the two of them were staying in tonight and no one else would be treated to this view. 

“How’s your back feeling?” Kira asked.

Mammon shrugged again. “Better. That cream thingy you used must’ve helped.”

“That’s a relief. Satan made it, so I was wary…”

“S-Satan made it?” Mammon growled, wishing he could claw off his back. “Gross.”

“You’re petty,” she noted.

Wow, if she thought this was petty, imagine how she’d feel if she looked in her bathroom bin and found all his brothers’ stuff.

After that, Kira disappeared into the bathroom for a bit. Mammon was left alone, and he flicked on the TV, where the last episode of TSL was paused. He didn’t want to lose her place, but was intrigued by the still frame it remained on, with a scene of Henry - Mammon guessed it was him, but he wasn’t a TSL expert like Levi - tied up at the hands of that season's villain. Mammon didn't know what was going on with him, but his mind drifted to imagine Kira in similar restraints. He snatched the remote and turned it off with the hopes of banishing the image from his mind. His DDD also happened to buzz at that moment, so he distracted himself by reading through a series of irritated messages on the brothers group chat.

~ The Demon Brothers (New) (7) ~

Levi  
MAMMON

Satan  
What’s he done now?

Beel  
So much for being nicer to him…

Satan  
I was just saying what you were thinking.

Levi  
MAMMON I FORBID YOU FROM TOUCHING MY MANGA OR WATCHING TSL OR PLAYING MY VIDEO GAMES WHILE YOU’RE STAYING WITH HER

Asmodeus  
Staying with her? 

Belphegor  
I hate you Mammon.

Levi  
Make it quite clear to your brothers that if I see any of them before breakfast tomorrow morning, I will make them wish I could PHYSICALLY kill them.

Levi  
That’s what Kira told me to tell you.

Lucifer  
With this ridiculousness, she might manage to physically kill me anyway.

Levi  
Great, you’re here Lucifer. Go and talk to Kira and get her to be reasonable. We were supposed to hang out tonight and finish the new episodes of TSL, but she’s dumped me for Mammon.

Satan  
I wouldn’t take her words lightly.

Beel  
Yeah. You should’ve seen her earlier, Levi. She was really mad.

Asmodeus  
Actually… I thought it was kind of sexy.

Levi  
I DON’T THINK YOU’RE UNDERSTANDING WHAT I’M TRYING TO SAY. SHE DUMPED ME FOR MAMMON.

Belphegor  
I side with Levi. I don’t want Mammon sleeping in MY spot.

Levi  
Well? Lucifer?

Lucifer  
If Kira wants to spend her night with Mammon, then I think we should respect her wishes.

Asmodeus  
WHAT?

Levi  
WHAT?

Belphegor  
WHAT?

Satan  
Are you crazy?

Satan  
Oh wait, we already know you are, but this is beyond that.

Levi  
LUCIFER I NEVER ASK YOU FOR ANYTHING BUT THIS ONE TIME I NEED YOU

Asmodeus  
That is such a lie.

Lucifer  
Going to see Kira after what she said earlier would imply that I have plans to apologise, which I don't.

Satan  
Ugh.

Belphegor  
So stubborn...

Mammon glared at his screen, making sure they’d all acknowledged the tick that confirmed he had read the messages and watching as they all started to furiously type at him, before he switched his DDD off entirely and discarded it on her end table. Kira, just leaving the bathroom fully washed up, would never have to know that they were talking about her.

“Done?” Mammon said, struggling to conceal his smile upon seeing her.

Kira approached him, coming really close to his face and breathing. “Minty fresh, right?”

“You’re gross,” Mammon grumbled, rolling across her bed and pressing his face into the sheets. He so wished he could seize her chin and lead her into a kiss, silencing her minty exhalation, but for now he’d have to settle with inhaling her scent from the place she slept.

His heart was just beginning to calm down, when he felt the movement on the bed next to him.

“What are you doing?” Mammon said.

He rolled around onto his other side, definitely not expecting to immediately be face to face with her.

“W-What are you doing?” he repeated, controlling the shakiness of his voice.

Kira looked right at him, and the corners of her lips twitched into a smirk. One of her arms had naturally fell across his side, and as she shifted it to a more comfortable position, she only managed to pull herself closer. Mammon supposed she was doing this on purpose to get a reaction out of him, but he also couldn’t help reacting as if it were genuine. 

“It’s too early to go to sleep,” he murmured.

She didn’t respond, but she definitely wasn’t ignoring him. Her eyes said that much, and they didn’t leave his face, even as she lay there silently. Maybe it should’ve felt awkward, but after the original shock at their close proximity had subsided, Mammon was just mesmerised by everything about her. Fondness, affection, or whatever this was wasn’t something a demon was used to feeling, but maybe the Avatar of Greed could get used to it.

“Does your back still hurt?” she whispered.

Mammon gasped a little, feeling the casual hand she’d placed round his back slide beneath his shirt and caress the lash marks.

“It’s not bad,” Mammon began, but he winced, giving away his true feelings.

“Can you turn away?” Kira asked tentatively.

Mammon nodded obediently, rolling back to his original position. He hated it. The wall was boring. The wall didn’t smile at him and make his heart beat almost out of his chest. The wall didn’t look adorable wearing his clothes. What was Kira doing back there? He didn’t think she’d moved...

Just then, he stopped thinking. Or, more accurately, his mind was flooded with a new emotion.

Soft kisses were being peppered across his back. Between his shoulder blades, Kira healed his injuries with her lips. Mammon struggled for air, but managed to question aloud what she was doing again.

“Shush,” she said, between kisses, “I’m making it better.”

Mammon chuckled a little, before he resumed his fight to catch his breath. “As if. You don’t have that power.”

Yes. Yes, she absolutely did.

“Aw, you’ll make me sad if you carry on like this,” Kira hummed, and she nuzzled her face into his back.

Well, if she carried on like this, Mammon was going to do something reckless, and his brothers would never forgive him for it.

“Oh Great Mammon,” Kira began, her tone reverting to casual teasing. She also stopped touching him, and Mammon immediately missed the feeling of her lips, soothing his wounds. “Can you use your demon powers to turn off the light?”

“I think you’re using me,” Mammon grumbled, but he went ahead with dimming the lights.

Kira released him entirely while she slid under the covers. Mammon did the same thing, and once they were both enclosed in the sheets, he could feel the warmth emanating from her human body more than ever before.

“I think ya’ bed’s too small,” Mammon muttered, struggling to get comfy while keeping his boundaries from her.

“I beg to differ,” Kira said in a hushed sing-song voice.

She snuggled into Mammon, who in turn clung as close to the wall as he could. She was relentless though, and he gave in, allowing Kira to rest her face against his chest. It was cruel of her really, to only allow him this much contact. He was craving so much more. He was never going to be able to sleep tonight.

“Do you want to hold me?” she asked innocently.

“I- I don’t think I can say no in this situation,” Mammon mumbled, “you’re already half on top of me...”

Kira smiled into the darkened room as she felt Mammon’s arms extend around her body, snuggling her close. They lay there like that for a few moments, comfortable, but both with their minds wandering dangerously.

“Are you asleep?” Mammon asked, after the moment had passed. She’d gone oddly still in his arms, and he couldn’t help worrying about his human.

“Of course not,” she muttered, “how quickly do you think I go to sleep?” After a moment of silence her curiosity got the best of her and she questioned, “why were you asking?”

“Just…” He hesitated. “Your- Your legs are pokin’ into mine. It’s gettin’ on my nerves!”

Kira giggled lightly. “Do you want me to sleep on the floor?”

“That- That’s not what I’m sayin’ either!” he rushed to protest. “In fact, ya’ better not go anywhere! I’m gonna hold you here all night, okay? I’m not lettin’ you go.”

In the dark, Kira’s silence made Mammon question whether he’d said the right thing. Maybe he was too needy. Maybe he should release her and go back to his room.

“Well, say something,” he prompted.

A tiny sob from Kira only made him panic, and he sat up, smashing his head on the headboard and then feeling like an idiot when her tears mixed with laughter.

“What’s wrong?” he asked, ignoring his bumped head and rushing to interrogate her. “Did- Did I say somethin’? Kira...”

He heard her swallow back the tears, and then roughly wipe at her eyes with little paws.

“Mammon,” she said, before pulling him back down into the bed, trying to encourage him to relax and to reassure him. She could feel his confused expression, even though she couldn’t see his face. “Just- Just listen.”

His concerned silence allowed her to continue.

“Thank you,” she managed. 

"That's all you had to say?" Mammon asked. He'd been expecting, or rather, hoping for something more. Something that would give him the excuse to silence her with a kiss.

“Thank you," she repeated. "I don’t say it enough to you.”

“I- I don’t see why you’re thanking me, stupid human,” Mammon said, gently flicking her on the forehead. “I’ve only ever got ya into trouble.”

She curled up into him more than she had before, and found her voice and tears muffled by his chest. His arms wrapped around her, cradling her to him. She’d never looked smaller and more vulnerable, even when she was having abuse yelled at her by demons at RAD, when Asmo was relentlessly flirting with her, or when Lucifer was giving her a particularly nasty lecture. This human that always put on a brave face, no matter what, looked weak for once.

“You’re so tiny,” Mammon muttered, “who woulda thought someone so small could be so strong?”

His thoughts were spilling out now, but he found himself not caring anymore. These were words that, in this moment, he thought she needed to hear. Words to affirm that she could cry in front of him, and he wouldn’t think any less of her.

“I don’t have to be strong, because I’ve got you,” she said weakly, between sniffles. “Mammon, you’re my safe place and you’ll… You’ll always be here, right?”

“You adorable, stupid human,” Mammon whispered, stroking her hair while she cried into his chest. “I’ll always be there. So, stop cryin’, you’re makin’ me feel all bad.”

“I’m sorry,” she sobbed, “I’m sorry you’re hurt. I’m sorry.”

Mammon rubbed his fist across his own eye, roughly banishing any tears. If she needed him to, he could be the strongest demon in the whole of the Devildom. 

“Don’t go apologisin’ like it’s your fault,” he whispered. “It’ll never be your fault.”

They both must’ve fallen asleep after that, the rhythm of Mammon stroking her head lulling Kira into the deepest non-Belphie induced sleep she’d had in all her time in the Devildom. For the first time, she wasn’t plagued by nightmares, because she could feel Mammon’s steady heartbeat against her all night, reassuring her that he wasn’t going to leave.

She could leave, but he never would. That was a silent promise between them that didn't need to be mentioned.

**Notes for the Chapter:**

> WOW! Thanks so much for all the support on this fanfic! If Mammon wasn't already one of my favourite demon brothers, he definitely is thanks to writing this, and I'm having so much fun living vicariously through my MC (*´▽`*)
> 
> I've got ideas on how I'll be wrapping this story up, and then I'm thinking of doing something different for the summer or something about the side characters (I'm a massive Solomon stan)... I'd love to hear what people would want to read!!


	5. Cuddling

**Summary for the Chapter:**

> Kira wakes up with Mammon and questions how she feels about him...

Kira stirred, her eyes struggling to open. There was no sunshine in the Devildom to creep in through the window and wake her, so she’d grown accustomed to waking once her own body clock decided it was time. With it being significantly lighter outside than it had been the evening before, she assured herself that it wasn’t wrong to try and climb out of bed, risking waking her sleeping demon. She just had to grab her DDD off the side, but her arms were pinned to her sides. She was locked into his hold and wasn’t going to complain about it.

Mammon hadn’t moved all night it seemed, which was surprising as he was always such a fidget whenever they watched movies together. She was still smothered in his embrace, just as she had been before they’d both fallen asleep. So instead of trying to escape, she pulled her head back as steadily as she could and admired her Mammon. 

His eyes were gently closed, his mouth slightly open and his chest moving up and down with the rhythm of his calm beating heart. His shirt had ridden up at the back, and he murmured incoherently at the cold air as Kira shifted her position and accidentally pulled the covers off him. She hurried to resume her original placement and even managed to extend her arm enough to pull the shirt back down. The temptation to touch his bare skin and make him squirm was there, but she forced herself to ignore it.

He was so perfect, she thought to herself, falling in love all over again… 

Falling in love?

Kira exhaled sharply, reprimanding her heart for coming to that conclusion without consulting her brain first. She didn’t think she loved him. How could she possibly define the complexity and heartache of what she felt for Mammon with a simple all-encompassing word like ‘love’?

Still, maybe saying it aloud would help her come to a conclusion. Kira’s lips parted and, so delicately that the words might have wandered into his dreams and settled there, she whispered to him.

“I love you.”

Why did it feel so comfortable? Why did the words prove so much and so little all at once?

She carefully wrestled her arm free of Mammon’s warmth and reached upwards, tracing a line from his hairline, down the sculpted bridge of his nose, to his chin. Never touching him and hovering just over his flesh, Kira could still feel the intense magnetism. She intuitively moved herself closer to him so that their bodies were flush against each other. His heartbeat was now more tangible than before and she wondered whether she was imagining the way it had quickened when she’d pressed herself against him. He was still asleep, she hoped.

Mammon stirred not long after, maybe alerted by the change in their proximity and the fire it had awoken in him, even as he remained physically asleep. He yawned and stretched out, his legs brushing against hers. Hesitating in opening his eyes, because he could feel Kira shifting and guessed that she was already awake, probably prepared to embarrass him for holding her so tightly all night, Mammon tried to roll onto his other side, but when Kira yelped, feeling him crush her arm under him, his eyes shot open.

“Are you alright?”

He had resumed the original position, so she was perfectly comfortable again. “Good morning,” she said, her soft smile making him feel vulnerable. “Did you sleep well?”

Mammon was alarmed at how close she was to his face. It would hardly take any effort to lean in and close that gap. Boldness brought on by his 7AM delirium, Mammon answered her question by leaning forward and pressing his lips to her forehead. If she’d been allowed to kiss him yesterday with no strings attached, then he was going to carry that through to his own privileges this morning.

“Why are you blushing?” she giggled, after he'd pulled back. “I’m the one that just got kissed.”

Mammon planted his face into the pillow self-consciously, but he regretted not making the most of looking at her, and swiftly returned to his position.

“Is your back feeling better?” Kira asked, her memory jogged so that she remembered the reason Mammon was there in the first place. Apparently it wasn’t just for cuddles, and she wondered what other excuses she could come up with in the future.

“My back…” Mammon also struggled to recap. “Oh yeah, it’s better. Not- Not that it hurt anyway.”

“Right, because The Great Mammon doesn’t feel pain,” Kira drawled. When she caught his disgruntled expression, she reached forward and tousled his bed hair. “Well, I’m glad it’s better.”

Kira slowly rolled over, and Mammon spotted one of her legs sticking out from under the covers, reaching to make contact with the cold floor.

“Where are you goin’?” Mammon said, grasping at the hem of his- now her shirt.

“I need to check my DDD, then I’ll make you a drink.” 

Kira started to reach towards the bedside table, but Mammon decided he wasn’t going to give up her undivided attention that easily, and tackled her back into the bed, even incorporating his legs to wrap around her and bring her back to him. She laughed, not putting up any fight and allowing him to pull her back into his chest.

“We’ll have to get out of bed at some point,” Kira said unenthusiastically. Behind her, Mammon was playing with her hair and rubbing his forehead against her back, pleading for attention.

“I don’t wanna,” he muttered, like a spoiled child.

She giggled again. “Neither do I, but I’m sure your brothers are feeling guilty right now.”

“Ha! Yeah right.”

“And I’m sure they all want to apologise,” Kira could barely convince herself of that fact.

“Again, nice of you to have faith, but you’re wrong,” said Mammon.

“Well I at least need some breakfast!” she laughed.

“Just ten minutes,” Mammon murmured against her back. The tingling feeling of his face pressed against her spine reduced her resolve to nothing within seconds.

“Okay,” she said. “Five more.”

“I said ten!” Mammon remarked.

“Shhh,” she hissed, but her body language as she fell back into him again and accepted her position as the little spoon, told him that she had no problem with ten, or even twenty minutes longer.

Maybe she would’ve gone so far as to allow him thirty minutes of extra cuddles, but they were rudely interrupted by a sharp knock on the door.

“Ugh,” Kira and Mammon both groaned.

“Pretend I didn’t hear it?” Kira raised her eyebrows.

Mammon grinned, but gave her a nudge, telling her to go answer it. While she went, he sat up, stretching his arms above his head. She glanced back at him while pulling the door lazily until it was half open, reveling in the way his muscles responded to the stretch.

“Good morning.”

Kira turned sharply to look at Lucifer, then once she’d registered who he was in her morning daze, shot him daggers.

“Good morning,” he repeated, a slight threat in his tone.

“Morning,” she answered civilly.

“Trust me, Kira, this is as painful for me as it is for you, but my brothers are furious that you’re ignoring all of them and I can’t get any work done with them coming in and out of my room whining about how much they miss you,” Lucifer explained, merely as a monotone response to her glare.

“Didn’t you miss me?” Kira asked, deadpan.

Lucifer didn’t answer, but his scowl said it all. “I’m here to- To apologise.” 

Kira was taken aback, both by his un-Lucifer like stutter and by the prideful demon’s willingness to admit he was at fault.

“I take it Mammon’s inside...” he continued, taking advantage of her frozen shock and entering her room.

“Well… Yeah- But, wait-” Kira began, she tried to grab Lucifer by the sleeve, but he slipped out of her grasp.

She hardly wanted to look, knowing already from the terrified squeak from Mammon and then the resounding silence from Lucifer, that he’d seen all he needed to.

“Oh, so you were giving him ‘that’ kind of treatment,” Lucifer muttered.

Kira came up behind him, slowly and almost ashamed. She followed the Avatar of Pride’s eyeline and understood that this didn’t look good for her. 

Mammon was in her bed, and the covers had bunched in the shape of her body on the side away from the wall, revealing that she definitely hadn’t ended up on the floor for the sake of decency. The demon had no shirt on (terrible foresight on his part that he’d decided that moment to get dressed), and everything else was beneath the covers still, so there was no confirmation of whether he was wearing pants at all. Then there was Kira’s outfit also. She was wearing Mammon’s shirt after all, oversized and with nothing to cover her legs. Yes, it was something she’d done for a while, with no strange connotations because no one ever saw her in it. But to open the door wearing it... She could fully accept that she’d let herself in for this. 

Lucifer turned to face her, and she prepared herself for an onslaught, but after opening his mouth to say something, he just sighed.

“I’m tired,” he said.

Kira stared at him.

Lucifer closed his eyes for a moment and rubbed his forehead. He then turned away from her altogether. 

Mammon flinched as his older brother’s intense glare fell on him.

“Mammon,” he began, and it looked as if it was paining him to say it, “come to breakfast.”

Kira had to cover her own mouth to stop the squeak of protest she’d been preparing in case Lucifer decided to attack Mammon there and then. She tried to read the Avatar of Greed’s expression, but he still seemed mostly traumatised by the whole situation.

Together, the two of them remained still until Lucifer had reached the doorway, where he shot them both another indecipherable look.

Kira and Mammon waited in silence until the sound of his footsteps had fully faded away down the hall. Kira dropped her arms to her sides and numbly turned to Mammon.

As if on cue, because just one moment of eye contact triggered it, they both burst out laughing. There was nothing objectively funny about what had just happened - in fact, Kira was terrified of what was waiting for them at breakfast, but in the moment, it translated into hilarity.

“I- I really thought he was gonna apologise just then,” Mammon said, wiping tears of laughter from his eyes. “How dumb am I?”

Kira had fallen into a heap on the floor, but at some point her laughter had subsided. She looked up at Mammon, disbelieving and said, “that might be the closest you get to an apology.”

Mammon nodded glumly, “s’pose so.” He then added, “guess even your powers don’t work on him.”

Kira wanted to ask what Mammon thought these ‘powers’ she had were, but she didn’t think her frazzled mind could take anything else. Instead, she headed quietly into the bathroom to wash up before breakfast and whatever that might hold.

**Notes for the Chapter:**

> I LOVE writing this so much!! I hope everyone's enjoying reading - just two more parts to go then I'm gonna get started on another fanfic for Obey Me <3
> 
> Took a bit of inspiration for my 'tired' Lucifer from that new chat pic of him at the desk.


	6. Apologising

**Summary for the Chapter:**

> At breakfast, the brothers have something to say to Mammon. Although maybe their intentions aren't pure...

After they’d both taken turns washing up, Kira and Mammon braced themselves and headed down to breakfast. Even though neither of them said anything, their usual banter was being exercised quieter than usual, and they were careful to check behind corners in case the others were waiting. It was stupid really; they would have to face them in a few minutes, anyway.

Once they were just outside of the dining hall, Kira pulled Mammon to the side, hiding them out of sight while coordinating a plan of action.

“We just have to get through this breakfast, then we’re off to RAD and that means I can ignore them if I want,” Kira said in a low voice, seeming to be reassuring herself more than she was reassuring Mammon.

“You say you can ‘ignore them at RAD’ as if you have any other friends,” Mammon muttered, gaining himself a humourless glare.

Braving their audience, Kira and Mammon puffed up their chests and entered the dining room. They tried to portray their hostility towards the other demons, making sure they didn’t forget that they hadn’t been forgiven yet, but they could feel more anger emanating from the brothers than either of themselves. Out of habit and confusion, Kira and Mammon’s shoulders slumped and they resumed the regular breakfast routine.

“Good morning lovebirds,” Asmodeus crooned, inviting Kira to sit beside him in her normal spot. “Did you spend a wonderful night together?” Something beneath his usual suggestive voice told her there was something on his mind - something irritating.

“How did you know we slept together?” Kira asked curiously.

“Sl-Slept together?” Levi spluttered.

“Disgusting,” Asmo hissed, watching Levi’s fork go clanging into his plate and littering pastry flakes over his area of the table.

“Disgusting,” Belphie repeated, looking pointedly at Kira. She got this odd feeling he wasn’t talking about Levi’s table manners.

Opposite her, Mammon had taken his regular seat. He was glancing up at Kira and then to the seat normally occupied by Lucifer with caution. It was still empty, but that didn’t mean the oldest demon brother had any less presence in his mind.

“Anyway, was it nice ignoring us?” Satan said. His tone tried to persuade them that he wasn’t bothered by what had happened, but his words betrayed that.

“Yes,” Kira said, but she noted a little whimper from Beel beside her and squeezed his hand to reassure him that she was just saying it for appearances sake. “It was oddly relaxing.”

Mammon guessed she was lying to them - she hadn’t seemed very relaxed for most of the time she’d spent with him, and, admittedly, neither had he (although that was for a whole different reason).

“Yeah right,” Belphie scoffed, “I’m sure Mammon kept you busy.”

“And speaking of Mammon,” Beel said. He pulled his hand out of Kira’s grip and placed both onto the table formally, all while looking around the others expectantly.

“I can’t believe we’re going to say this,” Belphie murmured.

“Better than Kira ignoring us forever,” Levi shrugged.

“And it’s not like we have to mean it,” said Satan.

“We’re sorry, Mammon,” they chorused, slightly out of time, but Kira scanned all of their faces and there was no denying that all of them had said it.

On the end, Beel added, “we should treat you better.”

Mammon’s jaw dropped and he gawked back at them, but the moment was short lived, and soon they were all facing Kira, anxiety and eagerness playing on their faces. The second oldest realised quite quickly that they weren’t really apologising to him at all, but he also knew he could never hate them for it.

“I don’t know why you’re looking at me when Mammon’s yet to accept your apology,” she said, words forcing them to resume staring at Mammon, daring him not to accept their apology.

Mammon wondered whether they might rip him to shreds if he didn’t.

“Alright. Apology accepted,” he said, feeling he’d prolonged the silence too long already.

Kira and Mammon met eyes, and she wondered why he’d accepted such a meager, half-hearted apology. After smiling at her, he resumed eating and seemed happy enough, so she didn’t want to bring it back up.

Mammon was always like that and she’d realised it. He was a peacekeeper, the glue of the seven brothers, and he would hold them together even if it meant he got torn apart. It was why up to this point she’d never acted against them, even though she’d seen him get hurt again and again. He didn’t want her to worry, and he didn’t want to ruin the harmony in the House of Lamentation.

Kira would accept this as a step forward, but she knew they were a long way from harmony. She’d had to coerce them this time, but at some point she hoped a time would come where they wouldn’t need prompting.

Everyone quickly slipped back into the normal breakfast routine after that, as if there had never been a rift in the first place. Mammon and Kira were teased by Asmo about their night together, Belphie and Satan added passive aggressive comments wherever they fit and Beel kept stealing from her plate (something she allowed because his poor attempt at subtlety was cute). There wasn’t long though before everyone left the table, aware that if they spent any longer rekindling their brotherly relationships they’d be late to their first lesson. Kira and Mammon took their time, letting the others get a head start.

“Hey,” Mammon said, tapping her on the shoulder.

Kira ground to a halt. “What’s up?”

“This- This week at school, can you just-” he paused, humming nervously as he worked out what to say. “Can’t ya just stay next to me? All the time. I don’t want ya leavin’ my sight, understand?”

She reared, starting to protest for her freedom, but was silenced completely when Mammon suddenly held her at her waist. She was jerked forward into him, and his arms slid up her back, securing her against his chest in a hug.

“Mammon, why-”

“Shhhh!” he said, pulling her even tighter and muffling her in his torso. “I don’t want you askin’ me questions about this. I just need ya to trust me. I don’t wanna spend a second without ya this week. Scratch that - ever again!”

He was always possessive, but this time it seemed to stem from more than just petty jealousy. There was something very serious, a little unnerving, yet still comforting, in the intensity of his expression. He looked away from her - there was something there he didn’t want her to see. Worry. Mammon was worried about her, and having spent last night getting a taste of what it would be like being with her as more than just friends, he only wanted to protect her more and preserve her life so that eventually, he would be able to be with her - forever. She had to avoid getting eaten by her demon classmates for Mammon to be in with a chance.

“I want you to remember,” Mammon said, releasing her slightly and then placing his hands on her shoulders so she was forced to look right at him, “that I’ll always save you, no matter what.”

Kira held her breath, eyes darting down to his lips that were drawn into a slight scowl. He looked sexy when he got tense like this, and it took all her restraint not to take advantage of it.

“Just like you helped me last night,” he continued sincerely, “I wanna help you more.”

“You already do more than enough,” Kira uttered. “It’s why you’re my favourite,” she added, so quietly that Mammon did a double take.

“Wait! What did ya just say? Am I your favourite? Was that what ya just said?” Like an excited puppy, he jumped up and down, pointing and shouting.

Blushing, Kira turned away and started towards the exit, shaking her head and swearing to Mammon that she hadn’t said that - that she didn’t have favourites, but she knew what had been affirmed last night. She was in love with Mammon, and she loved him most of all.

**Notes for the Chapter:**

> This is the final (official) part of this fanfic - although I'm doing a bonus chapter too, which will explain what happened to give Mammon the lash marks in the first place.
> 
> It's been so much fun writing and I hope everyone's enjoyed! Thanks for reading <3


	7. Bonus

**Summary for the Chapter:**

> Bonus Chapter: Mammon overhears some demons talking about his human at RAD. He decides to scare them away from her for good.

**Notes for the Chapter:**

> This little bonus chapter is set a day or so before the events of this fanfic, and it'll explain the injuries on Mammon's back and his other protective actions towards Kira.
> 
> I'm not 100% sure what each individual reader classes as violence, but this chapter shows a bit of it (nothing too graphic).

“Sorry teach, but I’ve got a human to get back to, so let’s save this for another time,” Mammon said.

He’d been stopped trying to slide out of the classroom with Kira and the others by a very unhappy alchemy teacher.

“I hope you understand, Mammon, that I don’t accept failures in my alchemy classes. Particularly failures who belong to the RAD student council. Being in your role means you have to take responsibility for your actions.”

“Go on ahead,” Mammon ushered Kira and the others out of the room, which an irritable Satan and Asmodeus seemed to have no issues with.

Right before turning away out of sight, Kira smiled at Mammon and said, “I’ll save you half of my ChocoCrunch.”

Mammon grinned back at her, his heart once again beating out of his chest simply at the kind gesture from his human. Even with a lecture from his alchemy teacher that would continue through most of lunch, the promise of half of Kira’s ChocoCrunch kept him in high spirits.

The lecture ended up taking all of break, in classic style for that teacher in particular. Mammon, deciding filling his stomach was more important than getting to his next lesson, headed to the vending machines. While he used his last few Grimm to grab a cold drink, he wondered whether Kira might ask the others where he was and he was grinning hopelessly until he heard some aggressive voices from just down the corridor.

“That human-”

“Not the sorcerer, of course.”

“Well obviously the girl.”

“It’s about time some big strong demon grabbed her by the waist and taught her where her place is in the Devildom.”

“You’re gonna be that demon, right Armaros? You’ll show her that she’s a weak, pitiful human.”

“Yeah. That stupid little human’s going to kneel before me and I’ll make sure she knows where her place is. None of the Princes of Hell will be around to save her - more accurately, they won’t even know she’s gone. She'll be screaming for help, but no one'll hear her. Then once I’ve had enough of her pleasuring me, I’ll devour her, real slow. She’ll be kicking and crying and I’ll just laugh and step on her frail human body-”

“Ah, you’ll be stepping on her, huh?” Mammon said, emerging from behind the vending machine. As he approached the three demons, he crushed the can he clutched in his fist into dust. So much for the Grimm he’d wasted to buy it.

Armaros and his two idiot friends stood their ground. Of all the seven brothers that could’ve heard them, Mammon was the least threatening of the lot. He was a known pacifist, too stupid to pass Devildom history and too weak to stand up to even his youngest brothers, so they thought there’d be no issue shrugging him off.

Mammon got real close to Armaros, his demon form flickering in and out of existence as he replayed the words he’d just heard in his head. He could feel his anger swelling, but knew she wouldn’t want him to do anything rash. “You’re gonna eat my human, you say?” Mammon said, raising his eyebrows.

Armaros stood his ground, his own demon form doing the same thing, and a spiked tail forming and then disappearing a few times over. “Well, Mammon, I’d save you a bite, of course.”

Their foreheads were hardly an inch apart, and Mammon’s eyes glowed with rage.

“If you ever lay a hand on her, I’ll destroy you,” Mammon seethed. He’d never wanted a fight this much before, but hearing someone talk about Kira like that had awoken his instincts and he couldn’t help imagining mounting Armaros’s head on a stake and then throwing that stake into a pit of lava.

“She’s just a human. Why do you care?” Armaros said, stirring the pot. He wasn’t about to flee. He fully believed he was as strong as the Avatar of Greed. “Unless, you’re really as weak as they say? The Great Mammon, bound to a normal human by a pact. Pitiful, really. But, you don’t have to worry. When I’m done with her, your pact won’t exist anymore - because she won’t exist anymore. I’ll make sure not even one drop of her blood remains in the Devildom and you can believe it - I'm a very thorough demon.”

Mammon wondered why he’d even let Armaros continue speaking. From the moment he’d said that she was ‘just a human’, he’d condemned himself to being beaten within an inch of his life. She wasn’t just a human. She was the most radiant being in the whole world. She was the only person he’d do anything to protect.

His demon form now firmly in place, Mammon raised one hand and in a movement that was so swift Armaros couldn’t even see it coming, he had clasped it around his neck. With just that grip, he raised Armaros into the air, so that his feet were dangling a short way above the ground. The weaker demon gasped for air, his jagged tail thrashing around. The power and fury he was exerting was getting to Mammon’s head, and he hardly felt anything, even as Armaros’s tail lashed his back, carving smooth slices that bled against his uniform.

“You’re gonna kill him!” one of Armaros’s friends cried from a distance. 

Understandably, both of them had backed up in awe of Mammon’s real power. Classic demons, Mammon thought. Loyalty only meant this much.

“I hope I kill him,” Mammon growled, tightening his grip and then loosening it, again and again, teasing Armaros with the possibility of escape and then showing him that that wasn’t going to happen. “I’m gonna use you as an example,” he spat, “an example of what’ll happen if anyone comes near her.”

Mammon released Armaros and, weakened and out of breath, he fell into a heap on the hard school floor. Armaros raised his head slightly, massaging the bloody claw marks pierced around his neck and then staring at his hand which was coated in a thin layer of his own blood.

“What are you gonna do to me?” Armaros managed. He smudged some of the blood from his hand onto his cheek and then his lips tweaked into a smile, so that he looked more deranged than ever. “Because whatever you do, it can’t be as bad as what I’ve imagined doing to your precious human- Guh-”

Armaros grunted as Mammon pressed his foot down on his body, crushing his stomach with his heel. He fell limp and Mammon decided he’d had enough. He didn’t enjoy delivering pain - even to a demon this disgusting, and the voice in the back of his head, the little Kira shaped angel on his shoulder, reminded him that he shouldn’t stoop to the level of the other demon.

But as he began to retreat and Armaros’ friends rushed to his side, trying to cover the wounds on his neck that seeped deep red, the defeated demon reached out his tail in one last provocation, winding it around Mammon’s leg. It was hardly enough to stop him, but Mammon halted.

“Whatever you do to me, she’ll never be safe,” Armaros uttered, knowing that although Mammon hadn’t turned back to him, he was hanging onto every word. “There will always be someone waiting for the chance to take her away from you. Can you handle it? How much would you really risk for her?”

Mammon refused to appease him. He didn’t want to turn around, just in case the lesser demon could sense the terror in his face.

“I’ll risk everything for her,” Mammon declared.

He composed himself then reached down. In a move that was more to incite fear and scare Armaros away for good than to genuinely harm him (even the claw wounds on his neck would heal pretty quickly for a demon), Mammon reached down, taking the end of the tail, unwrapping it forcefully from his lower leg and bending it sharply until it produced a snapping sound.

Bones broken, Armaros screamed. Mammon left him writhing in pain. 

Any other day, Mammon would’ve worried about how much Lucifer would tell him off if he found out about the fight, or about the throbbing pain now emerging on his back from searing lash marks, but his mind - as it now often was - was only occupied by thoughts of Kira. He was never letting her out of his sight again.

**Notes for the Chapter:**

> Thanks so much to everyone that's read this fanfic, I hope you've enjoyed as much as I've loved writing it!! <3
> 
> I'd love to interact with people and make some new moots: (my twitter is @AsmoEnthusiast). I'm also working on a summer fanfic involving all the brothers so any feedback here would be great for my future writing!


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